Redirects

[tylerfraser]

If I redirect page A to page B does page A need to exist before Google sees the redirect. Or can I just put up a redirect and delete page A.

If the page doesn't need to exist: You have all your redirects in place for a website. You want this website to redirect to another website. You completely delete the website and put up the htaccess, there should be no problem with this, because the redirects are in place correct?

Thanks

[MikeTek]

Think of Googlebot like a web user (who happens to be somewhat aimless and browses without JavaScript support).

Googlebot requests a page that it finds by A) following a link on another page, B) following a reference in a sitemap.xml file or C) some other usage data we don't know about (i.e. it scraped the link from a source it doesn't "officially" have access to or users have hit that page frequently with Google toolbar installed, etc).

This is a basic server request for the page. The server gets the message "load this URL" - if there's an .htaccess 301 redirect in place, it does not matter whether the page would ordinarily display content, because the server never gets to that point. It handles the redirect first.

I'm hung up on the second part of your question. "If the page doesn't need to exist...you want this website to redirect to another website." I'm not sure under what circumstances you'd need to do this. If the page doesn't exist, it shouldn't be referenced anywhere on the web, and if it's not referenced anywhere on the web, there's no need for the redirect.

Perhaps you're planning to set up the page as a vanity URL - such as a short URL, for easy reading/remembrance.

In short, for whatever reason you want to achieve this, .htaccess bypasses the need for the first URL to exist - it works on the request for that page, whether the page is there or not, the redirect will bypass it and work properly.

[ufmedia]

To your first question: Redirects are done for pages that presently exist and have been indexed by Google, not for pages that don't presently exist on a website.  So if it's a page that has already been indexed by Google, you would implement a 301 redirect to point the old page and most of its link juice to the new page.  (Not sure if this answer is what you were after - maybe I don't get the question?)

As to redirecting an old site to a new domain: I suppose you could technically delete the old pages when you put up the htaccess file with the redirects to the new pages.  However, I'd strongly caution against doing this in case you need to access the old content for some reason.  The crawler won't be able to get at it, because as soon as it hits the server it will trigger the htaccess file which will forcibly send them to the new URLs.  I've occasionally had to access an old site's content, so I'm glad I didn't delete it entirely.